There is known an asynchronous line-fed motor (cf. French Pat. No. 2,062,622, Cl. H 02 K, of 1971) comprising an inductor with a concentrated multiphase winding and a magnetic circuit composed of a number of separate laminated cores arranged transversely to the direction of travel of the magnetic field; the motor further includes a secondary element having a current-carrying portion mounted on a magnetically conducting base.
The motor under review has a limited efficiency and develops a relatively low tractive effort because of the non-uniform, i.e. stepwise, distribution of the magnetizing force inside the inductor.
There is further known an asynchronous line-fed motor (cf. an article by A. D. Popov and V. A. Solomin, entitled "Konstruktivnye ispolneniya asynchronnykh electrodvigateley s poperechnym zamykaniyem magnitnogo potoka" /"Designs of Asynchronous Motors with Transverse Closure of Magnetic Flux"/; the article is deposited with TsNIITEI under the Railway Ministry of the USSR, registration No. 663/78) comprising an inductor with a concentrated multiphase winding and a magnetic circuit, and a secondary current-carrying element separated by an air gap from the magnetic circuit which is composed of laminated cores. Each of the cores is formed by rods linked by a yoke. The laminated cores of the magnetic circuit are combined into two groups. The lamination of the cores of the first group is perpendicular to that of the second group. The cores of the second group connect adjacent laminated cores of the first group.
The inductor of this motor is serrated on the side of the secondary element in the direction transverse to that of travel of the magnetic field; this accounts for a non-uniform distribution of the magnetizing force in this direction, which, in turn, explains the low tractive effort and low efficiency of the motor.